vectortermlist.h

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/* Copyright (C) 2011,2012,2017 Olly Betts
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#ifndef XAPIAN_INCLUDED_VECTORTERMLIST_H
#define XAPIAN_INCLUDED_VECTORTERMLIST_H

#include "xapian/types.h"

#include "net/length.h"
#include "termlist.h"

class VectorTermList : public TermList {
    std::string data;

    const char * p;

    Xapian::termcount num_terms;

    std::string current_term;

  public:
    template<typename I>
    VectorTermList(I begin, I end) : num_terms(0)
    {
        // First calculate how much space we'll need so we can reserve it.
        size_t total_size = 0;
        for (I i = begin; i != end; ++i) {
            ++num_terms;
            const std::string & s = *i;
            total_size += s.size() + 1;
            if (s.size() >= 255) {
                // Not a common case, so just assume the worst case rather than
                // trying to carefully calculate the exact size.
                total_size += 5;
            }
        }
        data.reserve(total_size);

        // Now encode all the terms into data.
        for (I i = begin; i != end; ++i) {
            const std::string & s = *i;
            data += encode_length(s.size());
            data += s;
        }

        p = data.data();
    }

    Xapian::termcount get_approx_size() const;

    std::string get_termname() const;

    Xapian::termcount get_wdf() const;

    Xapian::doccount get_termfreq() const;

    TermList * next();

    TermList * skip_to(const std::string &);

    bool at_end() const;

    Xapian::termcount positionlist_count() const;

    Xapian::PositionIterator positionlist_begin() const;
};

#endif // XAPIAN_INCLUDED_VECTORTERMLIST_H